Such an optoelectronic semiconductor component is known and is used to modulate the intensity of the light beam supplied to the optoelectronic semiconductor component. Quantum films are used as semiconductor structures with carriers localized in at least one dimension, which are isolated from each other by respective barriers. The quantum-supported Stark effect is used to modulate the intensity of the light beam, which causes a change in the absorption spectrum of the optoelectronic semiconductor component in the area of the absorption edge (discontinuity) from the effect of an external field: the displacement of energy from the heavy hole and electron of the exciton, which determines the absorption in the area of the absorption edge, leads to a strong absorption decrease in the energy range of the original absorption edge, and builds another absorption in the energy range below the energy of the above-named exciton. If the operating wavelength of the light beam going to the optoelectronic semiconductor component is placed in this latter range, it is possible to perform a field-dependent intensity modulation of the light beam through an absorptive and/or an interferometric extinction, by varying the electrical field applied to the p- and n-layer of the optoelectronic semiconductor component.
It is a disadvantage of the known semiconductor component that a number of quantum films, separated by respective barriers, must be used to obtain a sufficiently large effect: the change in intensity of the supplied light beam that can be achieved with one or a few isolated quantum films is insufficient, at least in practice. However, this number of quantum films causes the existing fundamental absorption of each of these individual quantum films to add up to a disadvantageously high total fundamental absorption, so that an unwanted fundamental attenuation of the light beam supplied to the semiconductor component occurs in the zero field case. It is a further disadvantage of the known semiconductor component that a high modulation field is required to sufficiently modulate the supplied light beam.
Optoelectronic semiconductor components for modulating the intensity of the supplied light beam are known, which have a number of quantum films that are only separated by thin barriers. The thus obtained coupling of the quantum films results in a so-called superlattice structure, in which a delocalization of the carriers that are concentrated in the quantum films takes place across the entire superlattice structure, due to the quantum-mechanical tunnel effect. In the zero field case, these expanded conditions of the carriers in the superlattice structure are quickly localized in a few quantum films, due to the effect of an electrical field (Stark localization): this localization of the delocalized carriers across the entire superlattice structure, caused by the electrical field, leads to a strong absorption increase in the center of the soft absorption edge in the zero field case, and to a reduction of the absorption in the upper and lower range of the absorption edge. Due to the so-called Stark-ladder transitions, an absorption increase takes place in the low energy spectrum range of the absorption function of the optoelectronic semiconductor component, which manifests itself in a stronger red shift in the absorption edge than in the case of the quantum-supported Stark effect.
A disadvantage of the Stark localization is that the absorption edge is even blurred in the zero field case due to the Stark-ladder transitions, which in turn leads to an unwanted fundamental attenuation of the light beam supplied to the optoelectronic semiconductor component, and to a decrease in the effect that is used for the modulation, due to the blurred distribution of the oscillation intensity. This disadvantageous effect forces the selection of an operating wavelength of the light beam supplied to the optoelectronic semiconductor component to be far removed from the absorption edge. However, a displacement of the operating wavelength from the energy range immediately in front of the absorption edge to lower energies again has the disadvantage that the change in absorption characteristics caused by the electrical field decreases very quickly.